Changes in RNA content of the hypothalamus of mice following insulin administration

Cytoplasmic total RNA in neurons of the supraoptic nucleus, paraventricular nucleus, suprachiasmatic nucleus, and arcuate nucleus was determined cytophotometrically following a single intramuscular dose of 4 IU/kg insulin semilente. A significant decrease was observed after 3, 6, and 12 hours. A return towards normal values was evident after 24 hours and was full after 48 hours only in suprachiasmatic nucleus. Other hypothalamic nuclei did not reach the full normal value in the time interval examined, i.e. 48 hours post-injection.